Telephonic troubleshooting circuit for electric motor drives

Abstract

Electrical phenomena from electric motor drive circuitry is transmitted through telephone couplers, telephones, and telephone lines to provide signal data to a service technician remote from the circuitry for ascertaining the operative condition of the motor drive circuitry.

I claim: 
     
       1. An electric motor drive, the operative condition of which may be remotely ascertained with conventional telephone connection means and lines, comprising: circuitry means for energizing the electric motor, said circuitry means having a plurality of test points providing operative condition responsive signals suitable for diagnosing the condition of the circuitry;   switch means having an input coupled to said test points for obtaining said condition responsive signals and having an output providing a selected condition responsive signal;   signal generating means coupled to the output of said switch means for generating audio tones indicative of the magnitude and polarity of said selected condition responsive signal and having a frequency suitable for transmission over conventional telephone lines;   a first audio telephone coupler connected to said signal generating means and connectable to telephone connection means and lines;   a second audio telephone coupler connectable to said telephone connection means and lines;   converting means having an input connected to said second audio telephone coupler for receiving said transmission signal and having an output, said converting means converting the audio tone transmission signal to an analog electrical output signal corresponding to the selected condition responsive signal;   indicator means coupled to the output of said converting means and operable by the output signal of said converting means for providing a remote indication of the selected condition responsive signal; and   means operatively associated with said couplers for obtaining voice communication over said telephone connection means and lines.   
     
     
       2. The drive according to claim 1 wherein said signal generating means includes modulatable base audio frequency signal generating means, said switch means being coupled to said base frequency signal generating means for modulating said base frequency signal in accordance with said condition responsive signal, and wherein said converting means includes demodulation means for providing the analog electrical output signal. 
     
     
       3. The drive according to claim 1 wherein said indicator means comprises a meter. 
     
     
       4. The drive according to claim 3 wherein said meter includes a scale and said signal generating means includes scaling circuitry for providing condition responsive signals suitable for the scale of said meter. 
     
     
       5. The drive according to claim 3 wherein said meter includes a plurality of scales and said signal generating means includes scaling circuitry for providing condition responsive signals suitable for the scales of said meter. 
     
     
       6. An electric motor drive, the operative condition of which may be ascertained with conventional telephone connection means and lines, comprising: circuitry means for energizing the electric motor, said circuitry means having a plurality of test points providing operative condition responsive signals suitable for diagnosing the condition of the circuitry;   switch means having an input coupled to said test points for obtaining said condition responsive signals and having an output providing a selected condition responsive signal;   signal generating means coupled to the output of said switch means for generating audio tones indicative of the magnitude and polarity of said selected condition responsive signal and having a frequency for transmission over conventional telephone lines;   a first audio telephone coupler connected to said signal generating means and connectable to telephone connection means and lines;   a second audio telephone coupler connectable to said telephone connection means and lines;   converting means having an input connected to said second audio telephone coupler for receiving said transmission signal and having an output, said converting means converting the audio tone transmission signal to an analog electrical output signal corresponding to the selected condition responsive signal; and   indicator means coupled to the output of said converting means and operable by the output signal of said converting means for providing a remote indication of the selected condition responsive signal,   said switch means being further defined as signal responsive, said drive further including a signal generator coupled to said second telephone coupler, and said drive including means connected to said first telephone coupler and to said switch means for operating said switch means responsive to signals from said signal generator.